The growth of undoped and -doped molybdates and tungstates of alkali-earth metals and BaSO4 has been investigated. Single crystals were grown by the flux method within the temperature range of 600–475 °C, using the ternary NaCl–KCl–CsCl solvent. Sizes of undoped crystals increase within the series tungstates < molybdates < sulfate and, depending on the cation, within the series . The ion tends to be reduced to with time in the chloride solution, but can be partly stabilized by the addition of alkali-metal carbonates or hydroxides. The incorporation of is governed by the coordination of the tetrahedron in the crystal. No significant doping was found for Ca and Sr compounds and only small amounts of Mn6+ were incorporated into and . Crystals with orthorhombic space group Pnma such as exhibit significantly higher doping levels. The distribution in each crystal varies due to manganese reduction with growth time. Temperature-, time-, and concentration-dependent spectroscopy of : was performed.